1. Field of the Invention
The present invention relates to a duplexing system, and more particularly, to a duplexing system and method for writing a reserve list thereof, by which a reserve list is conveniently set up during a processor error, and priority procedure order is forced to occur during a critical process.
2. Description of the Prior Art
Typically, in a system comprising a processor which can operate plural independent jobs, if that duplexing function is automatically performed by an auxiliary processor, owing to a single auxiliary or when error is generated in plural processors simultaneously, each reserve list is stored in memory in order of the error generation in a time sequence. That is, regardless which processor is important, the reserve list is written by the method in which error data of processor is sequentially registered in a reserve list in the error generation time order.
In the conventional writing method of a reserve list by which the reserve list is written in an error generation time order, if a processor item occupied at a middle portion of the list has to be deleted for an error restored processor to be eliminated from a list, the following order corresponding to the item is shifted ahead in one step as shown in FIG. 12A, whereas if processor item has to be inserted in a middle portion of the list, the following item relative to the inserted item is shifted back in one step as shown in FIG. 12B. That causes a problem that the procedure is very complicated and a larger data storage memory is required.
Further, since error data is absolutely registered in a reserve list corresponding to an error generation time during error of critical processor, and not following the priority order, it causes another problem of a malfunction of the duplexing procedure.